Question: How would you disprove, experimentally, the assertion that white light passing through a piece of coloured glass acquires colour from the glass? What is it that really happens?Answer: To disprove the assertion (so repeatedly made) that “white light passing through a piece of coloured glass acquires colour from the glass,” I would ask the gentleman to observe that the glass has just as much colour after the light has gone through it as it had before. That is what would really happen.

Attributed. Found without source, for example, in Jon, Michael and Deborah Fripp, Speaking of Science: Notable Quotes on Science, Engineering, and the Environment. The quote appears to be a rephrasing of: “There are two possible outcomes: If the result confirms the hypothesis, then you’ve made a measurement. If the result is contrary to the hypothesis, then you’ve made a discovery”, as seen elsewhere on this page. Webmaster has been unable to find an original source for a direct quote either wording.

A formative influence on my undergraduate self was the response of a respected elder statesmen of the Oxford Zoology Department when an American visitor had just publicly disproved his favourite theory. The old man strode to the front of the lecture hall, shook the American warmly by the hand and declared in ringing, emotional tones: ‘My dear fellow, I wish to thank you. I have been wrong these fifteen years.’ And we clapped our hands red. Can you imagine a Government Minister being cheered in the House of Commons for a similar admission? “Resign, Resign” is a much more likely response!

As for science and religion, the known and admitted facts are few and plain enough. All that the parsons say is unproved. All that the doctors say is disproved. That’s the only difference between science and religion…

If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense. If, however, the existence of such a teapot were affirmed in ancient books, taught as the sacred truth every Sunday, and instilled into the minds of children at school, hesitation to believe in its existence would become a mark of eccentricity and entitle the doubter to the attentions of the psychiatrist in an enlightened age or of the Inquisitor in an earlier time.

It appears, then, to be a condition of a genuinely scientific hypothesis, that it be not destined always to remain an hypothesis, but be certain to be either proved or disproved by.. .comparison with observed facts.

There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.

While seeing any number of black crows does not prove all the crows are black, seeing one white crow disproves it. Thus science proceeds not by proving models correct but by discarding false ones or improving incomplete ones.

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- Carl Sagan